Search for: All records

Abstract ortho‐Phosphinophenol (oPP) is an unusual example of an air‐stable primary phosphine and a valuable precursor to a variety of useful organophosphorus compounds. The presence of PH₂and OH functionalities offers the possibility of intermolecular and intramolecular P⋅⋅⋅HO hydrogen bonding (HB). The close proximity of these two groups also offers the opportunity for intramolecular PH₂⋅⋅⋅HO dihydrogen bonding (DHB). This work provides experimental and computational evidence for these various types of interactions. In the solid state,oPPis associated by significant intermolecular P⋅⋅⋅HO hydrogen bonds as revealed by a single crystal X‐ray structural determination. Multinuclear NMR and IR spectroscopic studies, coupled with DFT computational studies, suggest thatoPPadopts multiple conformations in solution whose nature varies with the identity of the solvent. In the gas phase or non‐polar solvents (such as cyclohexane) an equilibrium between four conformations ofoPPis proposed. Interestingly,in silico, a conformational isomer having bifurcated intramolecular PH₂⋅⋅⋅HODHB(PP4) is found to be more stable than a conformational isomer having intramolecular P⋅⋅⋅HOHB(PP1). In polar solvents (S), NMR studies indicate intermolecular OH⋅⋅⋅S HBplays a dominant role in modulating³¹P NMR chemical shifts over a 17 ppm range.